Multilayer composite films having conductive metal patterns on at least one surface have been described for use in making sensors and/or test strips in biomedical and other applications. For example U.S. Pat. No. 7,073,246 describes a biosensor that includes an electrically conductive material on a polymeric base layer and electrode patterns formed on the base, with the patterns having different feature sizes. The patterns are formed by partially removing conductive material from the base using broad field laser ablation so that less than 90% of the conductive material remains on the base and the electrode pattern has an edge extending between two points. Other layers and features are also present, and such a device may be used, for example, in measuring blood glucose levels. In this and other applications, it is often preferred or required that the polymeric base layer be opaque for aesthetic reasons and/or to hide the internal circuitry of the strip. Suitable opaque polymeric films are known in the art, and typically contain a pigment and/or a voiding agent to produce the opacity. It is also preferred that the base material be flexible for ease of converting and production of strips, but also of adequate stiffness to allow easy insertion by the patient into the test meter. It will be apparent that the resulting product should be robust enough to withstand handling in the manufacturing process, sometimes under less than careful conditions.